The challenge of fetal dysrhythmias: echocardiographic diagnosis and clinical management.

OBJECTIVE: The present study aimed to evaluate the management of fetal cardiac dysrhythmias based on prior identification of the underlying electrophysiological mechanism. METHODS: We studied 36 consecutive fetuses with cardiac dysrhythmia. Rhythm diagnosis was based on M-mode, pulsed wave Doppler and tissue Doppler imaging (TDI). Only fetuses with: (i) incessant tachycardia (> 12 h) and mean ventricular rate > 200 beats/min, (ii) signs of left ventricular dysfunction, or (iii) hydrops, were treated using oral maternal drug therapy. RESULTS: The mean gestational age at diagnosis was 24.3 +/- 4.5 weeks. Twenty-one fetuses had tachycardia with a 1: 1 atrial-ventricular (AV) conduction. Based on ventricular-atrial interval, prenatal diagnosis was: permanent junctional reciprocating (n = 6), atrial ectopic (n = 6) or atrial-ventricular re-entry tachycardia (n = 9). One had atrial flutter, one ventricular tachycardia and four congenital AV block. Nine showed premature atrial or ventricular beats. Fifteen fetuses with incessant tachycardia, left ventricular dysfunction or hydrops were prenatally treated with maternal administration of digoxin, sotalol or flecainide. The total success rate (sinus rhythm or rate control) was 14/15 (93%). Seven fetuses were hydropics. Three of these died (one at 28 weeks of gestation, two in the first week of life). The prenatal diagnosis of dysrhythmia was confirmed at the birth in 31 of 35 live-born. No misdiagnosis was made using TDI. At 3 +/- 1.1-year follow-up, 33/35 children were alive and well. CONCLUSIONS: Fetal echocardiography could clarify the electrophysiological mechanism of fetal cardiac dysrhythmias and guide the therapy.

Left ventricular remodelling in outflow tract obstructive lesions during fetal life.

OBJECTIVE: Left ventricular (LV) remodelling in prenatally diagnosed LV outflow tract obstructive lesions such as aortic stenosis and aortic coarctation is important for prenatal counselling and postnatal management. The purpose of this study was to document the spectrum and the progression of different LV remodelling patterns and to identify prenatal markers of hypoplastic left heart syndrome (HLHS). METHODS: We studied 29 fetuses with LV outflow tract obstruction: 13 with isolated aortic stenosis, 14 with isolated aortic coarctation and two with combined aortic stenosis and aortic coarctation. Echocardiographic evaluation was performed 4 and 8 weeks after the first observation and at birth. RESULTS: None of the fetuses had HLHS (LV end-diastolic diameter z score higher than -2) at first prenatal echocardiography (24.5 + or - 3.6 weeks). Fetuses were divided into two groups: group A (n = 25) with a LV end-diastolic volume at birth > 20 ml/m(2); group B (n = 4) with a LV end-diastolic volume at birth < 20 ml/m(2) (LV hypoplasia). At first echocardiographic evaluation, the two groups showed a significantly different aorta to pulmonary ratio (0.44 + or - 0.08 vs. 0.86 + or - 0.14; P < 0.001); other LV echocardiographic features were not significantly different. The growth of the mitral (0.10 + or - 0.02 vs. 0.43 + or - 0.28 mm/week; P < 0.02) and aortic annulus (0.08 + or - 0.01 vs. 0.26 + or - 0.14 mm/week; P < 0.05) was significantly slower in group B. CONCLUSIONS: Our data suggest that LV outflow tract obstruction can progressively evolve in HLHS during pregnancy. A smaller aorta to pulmonary ratio was the only significant difference at initial echocardiographic evaluation in the two groups. Moreover, serial echocardiographic examinations are necessary to recognize fetuses at risk for HLHS caused by a subnormal growth rate of the mitral and aortic annulus.

Quantification of regional left and right ventricular longitudinal function in 75 normal fetuses using ultrasound-based strain rate and strain imaging.

Previous reports have demonstrated that myocardial velocities are not sufficiently sensitive in fetal heart studies. Strain (S) and strain rate (SR) imaging is a new noninvasive ultrasonic technique able to quantify regional myocardial deformation properties. SR imaging has a superior sensitivity than myocardial velocity for noninvasive assessment of ventricular function, but this technique has not been used in the fetal heart. Our aim was to evaluate the feasibility of S/SR imaging in the fetal heart and to study characteristics of myocardial deformation properties and their changes with the gestational age in healthy fetuses. We studied 75 normal fetuses (weeks gestation 25 +/- 4, no evidence of structural cardiovascular disease by 2-D echo and Doppler study) using S/SR imaging. Left (LV) and right ventricle (RV) peak myocardial systolic, early diastolic and SR values during atrial contraction were obtained but, for S, we measured only peak systolic values. The sample volume was placed in the mid-segment of LV septal, lateral and RV free wall. S and SR curves were obtained in all the studied population. Peak longitudinal systolic deformation was homogeneous in all the walls studied. Moreover, fetal myocardial S and SR during diastole were characterized by a higher deformation during atrial contraction than during early filling. Peak systolic and peak diastolic ratios of regional myocardial deformation properties significantly correlated with the gestational age. Inter- and intraobserver variabilities for S and SR parameters were < 15%, < 18% and < 13%, < 15%, respectively. SR imaging is feasible in selected healthy fetuses, with a limited reproducibility; we presented normal values for the fetal heart; S/SR during fetal life are homogeneous in both LV and RV; and longitudinal myocardial deformation properties increase with the gestational age.

Familial recurrence of congenital heart disease in patients with ostium secundum atrial septal defect.

AIMS: Ostium secundum atrial septal defect (osASD) is one of the most common cardiac malformations. Few data are available on the familial recurrence of congenital heart disease (CHD), in particular, in a large group of patients with isolated osASD. The aim is to investigate the familial recurrence of CHD in up to third-degree relatives from a large sample of consecutively enrolled patients with osASD, taking into account the influence of degree of relatedness (as number of relatives). METHODS AND RESULTS: From January 1998 to December 2002, we enrolled 583 patients with osASD and 408 healthy subjects, referred to our tertiary centre. We hypothesized that a positive family history required at least one relative with CHD to constitute a risk factor. In this model of analysis, the null hypothesis is a similar familial history between cases and controls. Among 583 patients with osASD, 109 (19%) had at least one relative with CHD. Among the 408 healthy subjects studied, only 23 (6%) had a family history of CHD. A familial recurrence of CHD was demonstrated in 72 of 312 (23%) patients with isolated osASD and in 37 of 271 (13.6%) patients with non-isolated osASD. Familial recurrence of isolated osASD was demonstrated in 22 of 312 patients (7%) with an isolated osASD and only in six of 271 patients (2.2%) with non-isolated osASD. The familial recurrence risk of isolated osASD in patients with isolated osASD was higher in sibs, especially in sisters (33.3%). CONCLUSION: This study underscores the role of genetic factors in the determination of CHD, particularly osASD. Our results could represent the basis for further studies to calculate a 'value of family history' to adapt the familial recurrence to the real size of each family group. In this way, we could select families with a 'tendency' to develop CHD, particularly osASD. In these families, we could analyse the genetic pattern to establish abnormalities and the bases of CHD.

Fetal supraventricular tachycardia diagnosed and treated at twenty-four weeks of gestation and after birth: a case report.

Supraventricular tachycardia is the most common clinically significant fetal tachycardia. The diagnosis is usually made at routine sonographic workup during the second-third trimester of pregnancy. Treatment goals are cardioversion to sinus rhythm and reversal of cardiac dysfunction. We describe a case of fetal supraventricular tachycardia diagnosed at 24 weeks of gestation. The first-line treatment was oral maternal digoxin and sotalol. This therapy was not sufficient for complete control of the tachycardia. Hence, second-line treatment with digoxin and flecainide was started and successfully achieved conversion to sinus rhythm. No adverse maternal side effects were noted during the 14 weeks of therapy. A normal male infant was delivered at elective cesarean section performed for obstetric indications at 38 weeks of gestation. A persistent junctional reciprocating tachycardia with a ventriculo-atrial/atrioventricular ratio > 1 was diagnosed following delivery at transesophageal electrophysiological study. At the age of 8 months the child is on therapy with sotalol (4 mg/kg/day) and flecainide (3 mg/kg/day) and is in good clinical conditions.